In a conventional communication system, account information is registered in a service provider server for a user of a multifunction peripheral. In this system, the user performs authentication procedures by accessing a mediation server via a personal computer and inputting the account information to the service provider server via the mediation server. When the authentication is successful, the service provider server generates an access token corresponding to the account information and transmits the access token to the multifunction peripheral via the mediation server. The multifunction peripheral transmits the access token to the mediation server for accessing a folder which corresponds to the account information and is stored in the service provider apparatus. The mediation server allows the service provider server to perform authentication using the access token. When this authentication is succeeded, the service provider server transmits data in the folder to the multifunction peripheral.